Marat Aukhadiev, Halil Hancioglu
The Framework with the rocketing popularity
Now, a few days after the Event-driven Microservices Conference 2019 in Amsterdam it’s time to share a recap about a great event, organized by the AxonIQ team at the end of September. It was a one-day conference on event sourcing and CQRS patterns in microservices. The highlight was of course, the rapidly gaining popularity Axon Framework which reached 2,5 Million downloads in the last year, a double of the year before. The conference talks were full of fair critics, useful tips and insights, and the audience was purely specialists: developers and architects.
It was opened with a keynote by Alberto Brandolini on importance of DevOps, explaining and showing on examples how architectural choices shape the interactions and the culture of an organization. Starting such an event with a DevOps talk might first seem confusing. But as the speaker pointed out, such things as creative culture and perfect clearness are vital for DevOps to enable delivery at high velocity. Those can be provided by sharply defined bounded contexts when using domain-driven design.
After an inspirational keynote, Allard Buijze continued with insights into the upcoming versions of Axon Framework and Axon Server. For example
- Graceful shutdown of the framework
- Improved “exception resilience”
- Axon Server status APIs
- API & UI improvements and
- Backup nodes & Multi-tier storage.
to improve Operations. Regarding modeling & design it’s planned to improve/introduce
- Dead-letter queues
- Ephemeral events
- Improve Event scheduling
- Aggregate polymorphism and
- Saga & Process Manager API.
In addition, Axon Server telemetry and Routing statistics in the next release will improve the observability.
The hottest news is that there will be a SaaS cloud solution for the Axon Server as a commercial product with SLA-backed support by AxonIQ. It is currently in pre-pre beta phase, available for test use by subscription on the Axon website.
Hard reality of Event Sourcing in Production
The audience then split to “Axon Inspiration” talks and “Axon In-depth” talks. The title “Day 2 problems in CQRS and Event Sourcing Building Axon-powered” immediately attracted our attention. The point was that despite of numerous benefits of CQRS and event sourcing, one faces big challenges after the “honeymoon phase“. The speaker Joris Kuipers (Trifork) warned and gave some tips:
- Rule of Thumbs for “Eventing”: Ignore what you don’t know
- App version compatibility: Implement forwards compatibility, accept downtime as inevitable
- Event Sourcing Overhead: Snapshots and aggregate caching is necessary
Topics also mentioned:
- Unmarshalling tagged events
- External event Processor Tips
- Expanded Aggregate State
- Dealing with Invalid Snapshots
- Query Projection Changes
- Deployment Planning
All this should be considered when deciding to use CQRS and event sourcing.
The conference further continued with hands-on workshops offered to get in touch with
- Event Storming
- Hands-on Event-Driven Microservices with Axon Framework (see https://github.com/AxonIQ/axon-quick-start)
- Reliable Event-Driven Systems through Chaos engineering
and the value of event stores with time-series analysis
After a coffee-break, Ben Runchy from Revel Health shared his experience in introducing the Axon Framework and how it helped his company to achieve a clearer architecture. By the way, we had great conversations with Ben – hope to meet you soon again Ben 😉
Critics of the Microservices practices
Finally, Allard Buijze (CTO of AxonIQ) talked about “Microservices, the sense, the nonsense and a way forward”. It was one of the fair critics talks, where he sensitized the participants to the challenges of microservice architectures, the biggest of which is “Event thinking”. The speaker explained what the typical mistakes are when designing microservices. Often modularity is mixed up with the number of deployment units. Domain-driven design in practice turns into the “Noun-driven design”, i.e. for each new business notion a new microservice is created. Allard also emphasized the need to consider commands and queries as much as events when designing event-sourced systems.
The conference has shown, that event sourcing and Axon Framework could be a good option for companies that are confronted with compliance and auditing requirements to be more backward transparent over a range of time. The other direct benefit for companies is the opportunity to analyze data to squeeze out more value.
It was a great developer’s event without any marketing. It was cool to talk directly with the developers of the Axon framework to get answers and solution recommendations for problems met in a project and to get insights to the Axon Framework’s architecture.
Axon has a very active rapidly growing community all over the world, which we are very happy to join. Hope to get the chance to visit this event next year and meet the Axon community again!